The invention relates to apparatus and a method for handling transfer of material, and in particular to handling transfer of flowable particulate material.
Many industries, such as the food and pharmaceutical industries produce products in the form of flowable particulate material. This can be for example, powder, dust, grains, pellets, tablets and capsules. Such material often has to be transferred from one place to another, and special apparatus is used for this purpose, due to the quantities and characteristics of the products involved. Product can be stored in silos, for example, which often include specially adapted outlets including valves and seals, and product can be transferred from one place to another in containers such as intermediate bulk containers, or IBCs, again often having specially adapted outlets.
A problem which has been experienced with handling of this type of product is that of contamination. Product can become contaminated by dust, dirt etc from the outside environment on transfer from one container to another by contact with apparatus surfaces which have been exposed to the outside. Furthermore, the product itself can be a contaminant, where trace residues from shipment of one product remain in the apparatus which is then used for shipment of a different product. Also, traces of material left behind on surfaces exposed to the environment after handling can present an environmental and/or health hazard.
It is an object of the present invention to seek to mitigate problems such as these.
According to the invention there is provided material transfer apparatus, comprising a flow-path for flow of material from a first site to a second site and means for providing a gas stream in the flow-path for removal of material from the flow-path.
The means for providing a gas stream may comprise a nozzle, or a plurality of nozzles operatively connected with a source of gas, and the or each nozzle is preferably directed to provide a as stream normal to the flow-path.
The means for providing a gas stream is itself preferably positioned substantially out of the flow-path and the flow-path may be defined by a wall or walls shaped to promote a toroidal flow of gas therein. Preferably, the flow-path has a substantially circular transverse section, the airstream being provided at a tangent to the circular section of the flow-path.
There may be vent means for escape of gas from the flow-path, and the vent means is preferably positioned at a distance above or below, in use, the means for providing a gas stream. This prevents any vortex effect of the vent from adversely disturbing the toroidal gas stream. The vent means may include gas extraction means.
The apparatus may have valve means for opening and closing the flow-path, the means for providing a gas stream being disposed to provide the gas stream to play on the valve means.
The apparatus may also be provided with seal means of the valve means, the means for providing a gas stream being disposed to provide the gas stream to play on the seal means.
The valve means may comprise a substantially conical or frustoconical element.
In one alternative configuration the flow-path may be defined by together, an outlet of a first container and an inlet of a second container, and the valve means may be disposed to obturate the outlet of the first container. The first container may comprise means for operating the valve means the valve means being raisable into the said one container to open the flow path.
The valve means may include a device to open a closure of the second container.
In an alternative configuration, the flow-path may be defined by together, an outlet of a first container and discharge apparatus adapted to be disposed between the first and a second container. The valve means is preferably a valve of the first container.
The discharge apparatus may comprise a frustoconical hopper, and may also include raisable probe means adapted to engage and raise valve means of the first container.
According to a second aspect of the invention there is provided a method of operating material transfer apparatus comprising a flow-path for transferring material from a first site to a second site, the method comprising the step of providing a gas stream in the flow-path before and/or after flow of product therethrough.
The method may comprise the step of providing the gas stream to play on surfaces of structures located in the flow-path, the structures comprising valve means and/or seal means of the flow-path.